A set of guy wires, guy line or guy rope also known simply as a guy, is a tensioned cable designed to stabilize a freestanding structure. Guy wires are often used with masts, wind turbines, utility poles, cell phone towers, and the like. One end of the guy is attached to the structure and the other end is provided with an anchor to secure the free end of the guy and place the guy in tension. The most common type of anchor is a pier or caisson that is driven into the earth having an eye or other attachment point for the free end of the guy. Another common form of anchor is a dead man anchor that uses a buried concrete block, log, or other similar structure that has the guy attached generally pointed to the structure. Often, a stake-like anchor is used to secure the free end of the guy to the dead man structure.
The wireless telecommunications industry has been growing steadily for a number of years. Guyed towers are one of the structures which are widely used in telecommunication industry. A guyed tower typically consist of a guy mast, guy wires, tower base, and guy anchors. Guy wires attach to different levels along its height, and connect to the ground by using guy anchors. Guyed towers rely on guy wires to provide vertical and horizontal supports or resistances to transfer lateral forces to the ground through guy anchors. The members which are connected guy anchor block (or dead man) and guy wires are called anchor shafts. Anchor shafts are used to transfer loads from guy wires to anchor blocks. Therefore, the strength of the anchor shafts is a key factor to ensure the safe of a guyed tower.
Anchor shafts are typically made of steel. The type of shaft shapes could be solid rods, angles, channels, I-beams, flat bars. Since anchor shafts are embedded below grade surface, they are fully exposed to soil. The shafts of guy anchors typically corrode over time. The shaft corrosion primarily affects the area of the shaft where exposes to soil. Corrosion may be caused by the nature of soil, by groundwater, by the electrolytes generated by a battery cell formed between copper grounding and the shafts, or by other factors.
Corrosion may lead to a significant loss of material in the anchor shaft over several years. The loss in section area of the shafts can result in the insufficiency in the tensile strength of the shafts to transmit force to the anchor block. If the strength is inadequate to resist the force from guy wires, the shafts will fail and cause the collapse of the tower.
If a guyed tower collapses, it could damage the facilities in the tower compound area and the properties nearby the tower, and even poses a great risk to human life. The replacing of a collapsed guyed tower is expensive and time consuming.